Enhanced the formation kinetics of CO2 hydrate using graphene oxide and L-methionine

Abstract

Although carbon dioxide capture and storage based on hydrate technology has the characteristics of recyclability, high safety, and low pollution, it is hindered by the harsh conditions and the slow rate of hydrate formation. To improve the formation rate and the storage capacity of CO2 hydrate, the effects of graphene oxide (GO) and L-methionine (L-met) on CO2 hydrate formation kinetics were studied in this work. The experimental results showed that GO could effectively promote CO2 hydrate formation, and its promotion effect was related to the concentration of GO. For the single GO system, when the concentration of GO increased from 0.005 wt% to 0.025 wt%, the total gas consumption increased by 7.83%–16.59% compared with that of the pure water system. It was found that the optimal concentration of GO in the single GO system was 0.015 wt%, in which the induction time was shortened by 59.68% compared with that of the pure water system. For the compound system of GO and L-met, a synergistic promotion effect for CO2 hydrate formation was found between GO and L-met, and the optimal concentration in the compound system was 0.015 wt% GO mixed with 0.15 wt% L-met. Compared with the pure water system, the induction time and the time required for 90% hydrate formation to complete (T90) were shortened by 74.79% and 55.17%, respectively. According to the morphological observation of hydrates, it was inferred that the L-met enhanced the hydrate formation and mass transfer. Compared with the published data, the compound optimal system of GO and L-met had a higher gas storage capacity and a shorter induction time for hydrate formation. This work is helpful for advancing the commercialization of CO2 capture and storage based on hydrate technology.